Many common bacteria are evolving resistance to more and more antibiotics. According to published reports, resistant bacterial infections killed 19,000 U.S. hospital patients (and contributed to the deaths of 58,000 more) in 1992. For instance, strains of Pneumococcus, which can cause ear infections, meningitis, pneumonia and blood infections, became resistant to penicillin and to four other antibiotics in just the last six years. Some 20 percent of TB microbes resistisoniazid, the treatment of choice, and gonorrhea microbes resist penicillin. More than half the known strains of Staphylococcus aureus, which causes blood poisoning, resist everything but vancomycin. Clearly, the need for a constant supply of new antibiotic materials is never ending. Accordingly, one object of the present invention is to provide a new antibiotic agent arbitrarily designated herein as PM-93135.
New antineoplastic compounds are also needed for treatment against several human carcinomas. Accordingly, another object of the present invention is to provide a new antitumor agent, namely the compound PM-93135. This compound is a thiodepsipeptide with significant inhibitory activity of RNA synthesis.
Yet another object of this invention is to provide pharmaceutical compositions for administering to a patient in need of treatment using the active compound described herein. Still another object is directed to the production of the active compound by controlled aerobic fermentation using a biologically pure culture of an organism capable of producing the active compound in appropriate nutrient media, and to methods for the recovery and concentration from the fermentation broth, and to the final purification of the active compound.